Technical Question for people who own headers/engine mods, or any Toyota Techs.

indecline · #1 (**permalink**) 06-24-2003, 04:13 PM

Hi,

I was wondering if anybody with a modified Tundra has experienced any problems with the PCM unnecessarily retarding the timing as a result of "false knock" being picked up by the knock sensor because of a "loud" K&N FIPK cone, supercharger, headers, etc.

I do know that many people have had problems, (though not necessarily with the I-Force, thats why I'm asking) with the knock sensor picking up "false knock" as the circuit is usually designed to pick up only "real knock" within the spectrum of sounds made by the stock motor. Headers used to be notorious for producing false knock and resulting in lost power - superchargers can do the same (although I'm assuming the module is replaced or programmed differently as part of the s/c install - yea? Nay?)

Does anyone here know anything about I-force's knock sensor or how sensitive it may or may not be? Has anyone had any problems with the PCM retarding the timing too much because of this?

Thanks for any info,

Jason

mustang67408 · #2 (**permalink**) 06-25-2003, 11:28 AM

From my understanding, PINGING or spark knock usually occurs at a specific frequency.(inside the engine)
Headers are outside of the engine and only change exh sounds, they should not cause a problem, the S/C is also not internal part of the engine and should not cause a problem.Gear nosie sounds nothing like spark knock, it has a diff frequency on a osciiloscope.
I have not run into any FALSE spark knocks on the I-FORCE. I had a CB radio 1 time cause problems, the coax was run next to the ecu. That was in a old 22r-E 4 cyl.

Explination: The knock sensor is a piezoelectrci device mounted to the cyl block, which generates a signal when exposed to vibration. When engine knock occurs vibration in the cyl block causes the sensor to generate a signal voltage.The sensor signal varies in AMPLITUDE depending on the intensity of knock.

Detonation occurs in the 7KHz range , knock sensor and ECU designs take advantage of this fact. Toyota uses a filter to distinguish between background noises and actuall engine knock.

Hope this is simple enough to understand
Hope it helps.
Victor

indecline · #3 (**permalink**) 06-25-2003, 01:18 PM

thanks man - great info!

Tim Dickson · #4 (**permalink**) 06-30-2003, 09:15 PM

Victor,
Heard anything new or old regarding vibrating driveshafts on 2 x 4 Tundra with V8 such as service bulletins or recalls?

Thanks,
Tim

mustang67408 · #5 (**permalink**) 07-01-2003, 10:15 AM

There are no TSB's or recall's that i am aware of, for drivelines.
Most vibrations we have , have been on Tundras with steel factory wheels, either the wheels are bent, or the tires that come from the factory are out of TOYOTA specs. To much roadforce, but the tire manufacturer says it is within their specs. This causes a gray area in specifications, Mostly they have been the GOODYEAR WRANGLERS, and the DUNLOPS. Other than that and the BRAKE VIBRATION TSB on some Tundras, there is not much more.

If you think you have a bad U jouint, take the driveshaft out and feel how the U joints move back and forth, they should be smooth and not binding, 2WD's do not need to be greased. (I Have no idea why they did this) 4Wds- can be greased.
Hope this helps,
Are you after any specific problem?
Victor

Tim Dickson · #6 (**permalink**) 07-02-2003, 06:48 PM

Victor,
I've been through the brake SB and everything seems fine for now, only been about 5000 miles +/-. I've also changed the wheels and tires. I found a set of Sequia wheels and tires (Firestone) on ebay for $250 with only 5000 miles on them. The Firestones stink too but they are better than the Dunlops. I'm putting on a set of Michelin LTX/MS's soon. The thing that really bugs me is the driveshaft vibration. I've also been through the carrier bearing alignment procedure described by a subscriber on this web site but had no success. I think the bearing may be worn by now because it's been almost 10,000 miles. I complained to the local dealer about it a couple of months ago when the brakes were being worked but the tech didn't "feel" anything when we went for a test drive. I'll take the shaft off and check the joints and the bearing. If that doesn't show anything obvious I'll take it to the dealer one more time and go from there (arbitration?). If I replace the bearing and my problems go away, will Toyota reimburse me the $$....will the problem come back in another 15000 miles? (this vib started at 15,000 miles)....what has all this vibration done to other bearings in the drivetrain (trans, engine, rear-end)?...

Thanks,
Tim

mustang67408 · #7 (**permalink**) 07-03-2003, 10:08 AM

First , definatly put on the MICHELINS, i love those tires.
SECONDLY- take someone at the dealership for a ride, and show them the problem.
At our dealer if the tech doesnt feel a problem, he then takes the shop foreman, if still nothing is found , the customer is called to come down and show us what they are feeling.
As far as a bad bearing hurting other bearings, That usually doesnt happen, i have see U joints go bad , and the customer has let it got due to lack of funds and after a while , come in to have it fixed without any other problems.

Just curious- do you feel the vibration in the wheel or in the seat of your pants? All the time or just certain roads? Any specific speed?

As far as arbitration, i am low man on the totum pole, and dont know anything about that, that usually deals with the service manager and toyota- so sorry i cant help ya there.

sorry if this isnt tomuch help
victor

Tim Dickson · #8 (**permalink**) 07-03-2003, 11:13 AM

Victor,
The vibration is a classic resonating vibration just like a bad u-joint would feel like. It comes on abruptly at 50 mph and stays until just about 60 mph which is strange because a bad u-joint vibrates at all speeds, at least the ones I been around over the years. As far as roads go, the smoother the road the more pronounced it is. Meaning you don't have road noise masking the vibration. I feel it in the steering wheel or any other hard mounted item in the cab such as the seat frame or door. I also can "hear" it since I'm so tuned in to it now. I think the local dealer is trying to blow me off because I didn't buy it there, I bought it at a dealer about 50 miles away. Do you think I'll have better luck at the dealer where I bought it? Can the carrier bearing be changed on this drive shaft or do I have to buy the entire shaft, if I thought about buying one? Can't believe I'm going through this with a truck of this quality.

Thanks,
Tim

mustang67408 · #9 (**permalink**) 07-03-2003, 12:01 PM

Just because you didnt buy a certain vehicle at a certain dealership should not matter, A TOYOTA IS A TOYOTA. (just my opinion) i cant speak for other dealers. But if your not having luck with that dealer, i would definatly try another one. Take someone at the dealer for a ride and show them the vibration, (wish you were closer so i could feel vibration and help more), you can also ask for a FTS inspection (field tech supervisor)(someone from toyota in your region)( But you didnt hear that from me)

Did you take the u joints down and feel them, make sure they move smoothly with no hard spots?
As far as the driveshaft carrier brg goes it can be bought seperatly. altho i have only seen a few fail ,in much older vehicles.
It is strange for a u joint to make the steering wheel vibrate.
youve got me really thinking and it is driving me nuts.
ill keep digging on this end
good luck

you have a V-8? or a V-6? (i forget)
any after market items such as ( bush gaurd? light bar?cb antenna?) i have had these type of items, cause wind noise vibrations. Just trying to eliminate any odd ball items
Victor

Tim Dickson · #10 (**permalink**) 07-03-2003, 04:07 PM

Victor,
It is a 2002, SR5 with V8. It is completely stock except the SnugTop hard tonneau cover on the bed (that couldn't be it, could it?). It may be worth taking off to eliminate it although now that I think about it, this vibration started about 3 months before I put that thing on there. I haven't taken the shaft off to check the u-joints yet but will do this weekend for sure. I've been thinking about telling the local dealership I want to meet with a field rep anyway. Guess I need to pay the $$ and join this club so I can read any applicable threads in Lon's garage. I've heard there is good stuff in there. I also heard they talk about an alignment problem with this driveshaft. Have you accessed Lon's garage before? seen anything applicable to this?

Tim

Johnny Law · #11 (**permalink**) 07-03-2003, 04:46 PM

I had this problem only once since I owned my truck. It was within break in period and I was on the highway. There was a modulating vibration somewhere in the drivetrain. It sounded like driving over a washboard, even my three year old asked what it was. I let off the gas and then got on it, hard. Whatever it was, the vibration went away and hasn't been back since (knock on wood). Never did find out what it was.

mustang67408 · #12 (**permalink**) 07-03-2003, 05:47 PM

I am not a member of the garage, and havent had very many vibrations that were not the tires or rims. None that i can remember that have been u joints (in 2002 tundras). The aligment itself, we have had cause the steering wheel the virbrate back and forth, but not with a vibration sound, i am very puzzled.
check the joints this weekend, and i you have time take off the shell (ya never know).
Then definatly get someone involved and show them the noise/vibration from the dealership or higher up field rep.
sorry i am no further help, i feel so helpless sometimes.
good luck
victor